His son, righthander Brad Peacock, was less than a minute away from throwing his first offering as the Astros’ starting pitcher Friday against the Oakland Athletics at Minute Maid Park.

Jerry, 64, once drove a trailer across the country, supporting the slow minor-league climb of the Astros’ new No. 4 starter. For years, the retired police officer – 33 years of service, he said — devotedly watched Brad’s warmup bullpen sessions. Used baseballs were collected as proof Brad was doing something real and lasting in the unforgiving world of pro baseball. When Jerry caught Brad’s pregame ball Friday before the A’s glided to the plate, it was like nothing had changed for father and son.

But Friday was different. Major League Baseball’s opening week. Brad’s former team, Oakland, in Houston for the first night of a three-game series. Jerry’s son back on a big-league mound for the first time in two seasons.

During the first inning of the Astros’ 8-3 loss to the A’s in an American League West matchup before a crowd of 18,197, Jerry paced. He walked up and down an aisle near the Astros’ (1-3) dugout. He stood along the edge of a concourse. He moved and swerved and circled, all while Brad used first-inning strikeouts of Oakland’s (3-2) Yoenis Cespedes and Chris Young to offset a right-field home-run blast by leadoff hitter Coco Crisp.

“I gotta tell you: Honestly, this is the first time I’ve ever been a little bit nervous about a baseball game,” said Jerry, whose casual shorts and Hawaiian shirt balanced his nervous fatherly pride.

He added: “I’ll watch him the whole time. But I don’t want to be around people I know while I’m watching and moving around.”

Jerry drove Brad’s truck to Houston while the pitcher finished spring training. The father then waited for the son to arrive.

The Astros’ historic opening night and American League debut passed. The Astros’ MLB record of 43 offensive strikeouts in three season-opening games occurred – the team hit 53 by the sixth inning Friday.

Jerry waited through it all. And when Brad walked on top of an oval dirt mound at 7:10 p.m., toed a white rectangular rubber and fired to home, Jerry’s year-and-a-half wait was finally over.

Like his father, Brad initially struggled to settle down. He gave up two walks in the first inning, put two more runners on in the second and hit 49 pitches (22 strikes) before the third frame even arrived.

But the 25-year-old righty — who went from a 41st-round pick by Washington in 2006 to one of the top pitching prospects in the A’s farm system — found space in the third, reaching five total strikeouts and keeping the Astros’ within a 1-0 deficit.

By the fourth, Brad was at 83 pitches (44 strikes). But he’d still only allowed Crisp’s first-inning solo shot and two overall hits.

“I started to feel better and I started to slow down,” the Astros righthander said.

A full fifth was too much. Brad was pulled after his 89th pitch – a sharp right-field double by Crisp – and the A’s eventually put up seven runs in a dragged-out frame that saw Oakland hit 8-0 and the Astros record their 23rd consecutive inning without a run.

Brad’s final line: 4 1/3 innings, three hits, two earned runs, three walks, five strikeouts and a loss.

It was an early picture of the 6-foot-1, 175-pound starter, who beat out Alex White during spring training for the Astros’ No. 4 spot.

“He did a good job of keeping it close,” Astros manager Bo Porter said. “But at the same time, it was too many deep counts. The pitch count got up there. And this early in the season, I’m not going to extend him past 95, 100 pitches.”

By the time Brad turned the ball over to Astros reliever Xavier Cedeno on Friday, Jerry was walking back toward the stands. Brad’s first Astros start hadn’t been smooth. But he’d battled and bounced back, temporarily keeping his struggling team alive and showing the promise of becoming the solid third starter the Astros must consistently produce this season to have any chance of staying competitive in the AL West.

When Brad hit his limit Friday, Jerry didn’t see a major-league pitcher anymore. Instead, a father simply saw his son.

“I don’t get to visit with him like I’d like to. But that’s the just the way it is,” Jerry said. “He’s a wonderful kid and he’s all about baseball. It’s just what he’s born to do. It’s what he’s always done.”

Athletics catcher John Jaso (5) high-fives teammate Coco Crisp after Crisp hit a solo home run off Astros starting pitcher Lucas Harrell during the fourth inning.

Athletics catcher John Jaso (5) high-fives teammate Coco Crisp after Crisp hit a solo home run off Astros starting pitcher Lucas Harrell during the fourth inning.

Photo: Brett Coomer / Chronicle

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Athletics outfielder Chris Young hits a three-run home run off Astros starting pitcher Lucas Harrell during the fifth inning.

Athletics outfielder Chris Young hits a three-run home run off Astros starting pitcher Lucas Harrell during the fifth inning.

Photo: Brett Coomer / Chronicle

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Athletics outfielder Chris Young (25) rounds the bases after hitting a three-run home run off of Astros starting pitcher Lucas Harrell, bottom, during the fifth inning.

Athletics outfielder Chris Young (25) rounds the bases after hitting a three-run home run off of Astros starting pitcher Lucas Harrell, bottom, during the fifth inning.

Photo: Brett Coomer / Chronicle

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Athletics outfielder Chris Young (25) celebrates his three-run home run during the fifth inning off Astros starting pitcher Lucas Harrell.

Athletics outfielder Chris Young (25) celebrates his three-run home run during the fifth inning off Astros starting pitcher Lucas Harrell.

Photo: Brett Coomer / Chronicle

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Athletics right fielder Josh Reddick (16) stretches to try and catch a foul ball of the bat of Astros second baseman Jose Altuve during the fifth inning. Reddick was injured on the play and was forced to leave the game. less

Athletics right fielder Josh Reddick (16) stretches to try and catch a foul ball of the bat of Astros second baseman Jose Altuve during the fifth inning. Reddick was injured on the play and was forced to leave ... more

Photo: Brett Coomer / Chronicle

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Athletics shortstop Eric Sogard (28) slaps a tag on Astros center fielder Justin Maxwell (44) for an out during the fourth inning. Maxwell was trying to advance to second base after an overthrow at first.

Athletics shortstop Eric Sogard (28) slaps a tag on Astros center fielder Justin Maxwell (44) for an out during the fourth inning. Maxwell was trying to advance to second base after an overthrow at first.